"uuid","repository link","title","author","contributor","publication year","abstract","subject topic","language","publication type","publisher","isbn","issn","patent","patent status","bibliographic note","access restriction","embargo date","faculty","department","research group","programme","project","coordinates"
"uuid:22ef551d-01b9-4efc-ba36-244de8e5a0ce","http://resolver.tudelft.nl/uuid:22ef551d-01b9-4efc-ba36-244de8e5a0ce","Electron beam irradiation of dimethyl-(acetylacetonate) gold(III) adsorbed onto solid substrates","Wnuk, J.D.; Gorham, J.M.; Rosenberg, S.G.; Van Dorp, W.F.; Madey, T.E.; Hagen, C.W.; Fairbrother, D.H.","","2010","Electron beam induced deposition of organometallic precursors has emerged as an effective and versatile method for creating two-dimensional and three-dimensional metal-containing nanostructures. However, to improve the properties and optimize the chemical composition of nanostructures deposited in this way, the electron stimulated decomposition of the organometallic precursors must be better understood. To address this issue, we have employed an ultrahigh vacuum-surface science approach to study the electron induced reactions of dimethyl-(acetylacetonate) gold(III) [AuIII(acac)Me2] adsorbed onto solid substrates. Using thin molecular films adsorbed onto cooled substrates, surface reactions, reaction kinetics, and gas phase products were studied in the incident energy regime between 40 and 1500 eV using a combination of x-ray photoelectron spectroscopy (XPS), reflection absorption infrared spectroscopy (RAIRS), and mass spectrometry (MS). XPS and RAIRS data indicate that electron irradiation of AuIII(acac)Me2 is accompanied by the reduction in AuIII to a metallic Au0 species embedded in a dehydrogenated carbon matrix, while MS reveals the concomitant evolution of methane, ethane, carbon monoxide, and hydrogen. The electron stimulated decomposition of AuIII(acac)Me2 is first-order with respect to the surface coverage of the organometallic precursor, and exhibits a rate constant that is proportional to the electron flux. At an incident electron energy of 520 eV, the total reaction cross section was ? 3.6×10?16?cm2. As a function of the incident electron energy, the maximum deposition yield was observed at ?175 eV. The structure of discrete Au-containing deposits formed at room temperature by rastering an electron beam across a highly ordered pyrolytic graphite substrate in the presence of a constant partial pressure of AuIII(acac)Me2 was also investigated by atomic force microscopy.","adsorption; atomic force microscopy; electron beam deposition; gold compounds; infrared spectra; mass spectroscopic chemical analysis; nanostructured materials; organometallic compounds; surface chemistry; X-ray photoelectron spectra","en","journal article","American Institute of Physics","","","","","","","","Applied Sciences","Imaging Science and Technology","","","",""
"uuid:939728f0-8257-47ec-bad3-c190723ea79d","http://resolver.tudelft.nl/uuid:939728f0-8257-47ec-bad3-c190723ea79d","Electron induced dissociation of trimethyl (methylcyclopentadienyl) platinum (IV): Total cross section as a function of incident electron energy","Van Dorp, W.F.; Wnuk, J.D.; Gorham, J.M.; Fairbrother, D.H.; Madey, T.E.; Hagen, C.W.","","2009","The total cross section has been measured for the electron induced dissociation of trimethyl (methylcyclopentadienyl) platinum (IV) [MeCpPt(IV)Me3], a Pt precursor often used in focused electron beam induced processing (FEBIP), for incident electron energies ranging between 3–3 keV. Measurements were performed for the precursor in the adsorbed state under ultrahigh vacuum conditions. The techniques used in this study were temperature programmed desorption, x-ray photoelectron spectroscopy and mass spectrometry. Two surfaces were used in these experiments, amorphous carbon overlayers containing embedded Pt atoms (a:C-Pt), formed by the electron decomposition of the Pt precursor, and atomically clean Au. The results from these three experiments revealed a comparatively low total cross section at 8 eV (4.2+/-0.3xE?17 cm2 on the a:C-Pt and 1.4+/-0.1xE?17 cm2 on the Au) that increases with increasing incident electron energy, reaching a maximum at around 150 eV (4.1+/-0.5xE?16 cm2 on the a:C-Pt and 2.3+/-0.2xE?16 cm2 on the clean Au), before decreasing at higher incident electron energies, up to 3000 eV. Differences in the measured cross sections between Au and a:C-Pt surfaces demonstrate that the substrate can influence the reaction cross section of adsorbed species. Temperature programmed desorption was also used to measure the adsorption energy of MeCpPt(IV)Me3, which was found to depend on both the substrate and the adsorbate coverage. The work in this paper demonstrates that surface science techniques can be used to quantitatively determine the total cross section of adsorbed FEBIP precursors for electron induced dissociation as a function of incident electron energy. These total cross section values are necessary to obtain quantitatively accurate information from FEBIP models and to compare the reaction efficiencies of different precursors on a quantitative basis. (doi:10.1063/1.3225091)","electron beam induced deposition; dissociation cross section; platinum precursor; temperature programmed desorption","en","journal article","American Institute of Physics","","","","","","","","Applied Sciences","IST","","","",""
"uuid:4a57b23f-e0a6-443a-894c-5d09c204ad45","http://resolver.tudelft.nl/uuid:4a57b23f-e0a6-443a-894c-5d09c204ad45","A critical literature review of focused electron beam induced deposition","Van Dorp, W.F.; Hagen, C.W.","","2008","An extensive review is given of the results from literature on electron beam induced deposition. Electron beam induced deposition is a complex process, where many and often mutually dependent factors are involved. The process has been studied by many over many years in many different experimental setups, so it is not surprising that there is a great variety of experimental results. To come to a better understanding of the process, it is important to see to which extent the experimental results are consistent with each other and with the existing model. All results from literature were categorized by sorting the data according to the specific parameter that was varied (current density, acceleration voltage, scan patterns, etc.). Each of these parameters can have an effect on the final deposit properties, such as the physical dimensions, the composition, the morphology, or the conductivity. For each parameter-property combination, the available data are discussed and (as far as possible) interpreted. By combining models for electron scattering in a solid, two different growth regimes, and electron beam induced heating, the majority of the experimental results were explained qualitatively. This indicates that the physical processes are well understood, although quantitatively speaking the models can still be improved. The review makes clear that several major issues remain. One issue encountered when interpreting results from literature is the lack of data. Often, important parameters (such as the local precursor pressure) are not reported, which can complicate interpretation of the results. Another issue is the fact that the cross section for electron induced dissociation is unknown. In a number of cases, a correlation between the vertical growth rate and the secondary electron yield was found, which suggests that the secondary electrons dominate the dissociation rather than the primary electrons. Conclusive evidence for this hypothesis has not been found. Finally, there is a limited understanding of the mechanism of electron induced precursor dissociation. In many cases, the deposit composition is not directly dependent on the stoichiometric composition of the precursor and the electron induced decomposition paths can be very different from those expected from calculations or thermal decomposition. The dissociation mechanism is one of the key factors determining the purity of the deposits and a better understanding of this process will help develop electron beam induced deposition into a viable nanofabrication technique.","dissociation; electron beam deposition; electron beam effects; electron beam focusing; heating; nanotechnology","en","journal article","American Institute of Physics","","","","","","","","Applied Sciences","Imaging Science and Technology","","","",""
"uuid:928de04c-9565-4bcd-89e4-eb6cfb02214b","http://resolver.tudelft.nl/uuid:928de04c-9565-4bcd-89e4-eb6cfb02214b","Synthesis of Nanostructures using Electron Beam Induced Deposition","Kruit, P.; Van Dorp, W.F.; Hagen, C.W.; Crozier, P.A.","","2008","","","en","journal article","Cambridge University Press","","","","","","","","Applied Sciences","Imaging Science and Technology","","","",""
"uuid:ffb57c20-8269-4399-878f-90cb3e71c3fd","http://resolver.tudelft.nl/uuid:ffb57c20-8269-4399-878f-90cb3e71c3fd","Sub-10 nm focused electron beam induced deposition","Van Dorp, W.F.","Kruit, P. (promotor)","2008","Work started with a critical review of literature from the past 70-odd years. The review shows that the physical processes occurring in EBID are generally well understood. By combining models for electron scattering in a solid and electron beam induced heating and knowledge of growth regimes, the majority of the experimental results was explained qualitatively. The review makes clear that several major issues remain. The fact that cross sections for electron scattering in a solid and electron-induced precursor dissociation are not well known, makes it difficult to interpret experiments where the acceleration voltage is varied. Related to this is the limited understanding of electron-induced precursor dissociation. The dissociation mechanism is one of the key factors determining the purity of the deposits and a better understanding of this process will help to develop EBID to its full potential. The growth behavior at the sub-10 nm regime was explored by writing lines and arrays of dots from W(CO)6. The smallest average values that have been found for the full width at half maximum, are 1.9 nm for lines and 0.72 nm for dots. These are world records for EBID and for the first time, it is shown that growth on this scale is determined by random processes. The deposits consist of so few molecules, that the counting statistics become visible. The result is that, despite identical conditions, deposits are not identical. The final deposited mass varies from dot to dot and dots do not nucleate exactly on the irradiated position, but randomly around it. This results in nonsymmetrical dots in the early stage of growth. More insight into the deposition process is obtained by monitoring the annular dark field signal during the growth. This revealed that the growth rate during the deposition is not constant. The method also allowed control over the growth, for instance to prevent the occurrence of a proximity effect. Atomic force microscopy measurements allowed quantification of the deposited volume. The distributions of the deposited volume as a function of dwell time bear a close similarity to Poisson distributions, which suggests that the deposited dots consist of a number of discrete units. From a fit of Poisson distributions to the volume distributions, it was concluded that the volume per unit is as small as 0.4 nm3. This volume is almost just as small as a single W(CO)6 molecule in the solid phase. The work described in this thesis opens up a whole new decade of feature sizes from 20 to sub-1 nm and brings the ultimate resolution of single molecules within reach.","electron beam induced deposition; nanometer scale; sub-10 nm; focused electron beam induced processes; scanning transmission electron microscopy; environmental microscopy; nanofabrication; electron beam lithography; poisson statistics","en","doctoral thesis","","","","","","","","","Applied Sciences","","","","",""
"uuid:0b66693d-4528-483b-99b0-8e5b3597da5a","http://resolver.tudelft.nl/uuid:0b66693d-4528-483b-99b0-8e5b3597da5a","Growth behavior near the ultimate resolution of nanometer-scale focused electron beam-induced deposition","Van Dorp, W.F.; Hagen, C.W.; Crozier, P.A.; Kruit, P.","","2008","","","en","journal article","IOP","","","","","","","","Applied Sciences","","","","",""
"uuid:d2c90024-896d-4721-99c0-5008c781932d","http://resolver.tudelft.nl/uuid:d2c90024-896d-4721-99c0-5008c781932d","The nucleation stage in electron beam induced deposition","Hagen, C.W.; Van Dorp, W.F.; Crozier, P.A.","","2008","","","en","journal article","IOP","","","","","","","","Applied Sciences","","","","",""
"uuid:e1330fb5-ef7a-4c53-986a-f81bdd98989a","http://resolver.tudelft.nl/uuid:e1330fb5-ef7a-4c53-986a-f81bdd98989a","Nanofabrication and growth processes with ultra-high resolution electron beam induced deposition on thin films","Van Dorp, W.F.; Crozier, P.A.; Hagen, C.W.; Kruit, P.","","2005","","","en","journal article","Cambridge University Press","","","","","","","","","","","","",""